Gems x Thunder Breathing
by knzwa
Summary: Imagine how it feels to be left behind by all the people you care about and will never return. Sacrifice of feelings and tears of a girl that will never be finished. "Why you left me? －"
1. Chapter 1

Hi all, this is my first time to write story of my original character of Kimetsu no Yaiba, I'm really sorry for grammatical errors and other mistakes, because English is not my main language, but I hope you can enjoy my story c:

Happy reading ~

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**Kimetsu no Yaiba**

**Credit: Koyoharu Gotouge**

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Saiwai Suzumi was a girl with maya blue-eyed, in the past, she lived with her family in town and became best friend of Zenitsu because their age were same.

Unfortunately, their friendship almost broken because Zenitsu suddenly disappeared from her life, she heard that he moved to another town without telling her.

Suzumi felt sad and lonely, she was just in her room everyday, actually she was mad, why Zenitsu left her? She didn't have another best friend besides him.

The older sister, Saiwai Kurumi, feel sorry with her sister's condition. She understood Suzumi's feelings.

Kurumi decided to enter Suzumi's room and sat next to her.

"_Nee-chan? _Since when you're here? how's the mission?"

Kurumi put her _katana_ beside her, she was smiling to her little sister while Suzumi's felt badmood.

"Why just smiling? Say something!"

"Suzumi, do you wanna learn about how to fight _oni _with katana?"

Hearing the word 'oni', her maya blue-eyes were wide. "_Oni? _Are they really exist?"

Kurumi just silent for couple seconds, "Yes, they are really exist, they eat human just like we heard from the stories." Kurumi closed her corn flower blue-eyes and controlled her breath.

"Then? You've been hiding it from me all this time?"

"_Nee-chan, _if that things really happen, why you didn't let me know it from the first?"

"I'm really sorry, Suzumi... Papa told me to don't let you know about this problem, because you're the only hope in our family."

"Then... Papa..." Suzumi felt tightness in her heart.

"P-papa... w-was k-killed by... d-demons?" Her whole body trembled, tears trickle from her eyes.

"Why did this happen? If I know papa fight demons, I'd join him, then papa wouldn't leave us." Suzumi had sobbed, she could not hold herself anymore.

Suzumi and Kurumi's mother passed away 4 years ago after giving birth their little sister who passed away too 2 days after their mom, and they had to lose their father two and a half years later.

Since that, they were just the two of them, if her sister left for a mission, Suzumi would be alone, but it's not a problem since Zenitsu became her best friend. Because of that, Suzumi felt devastated because of losing another person in her life.

Kurumi hugged her little sister, tried to calm her down. "Aren't you shy? Zenitsu will hear your crying sound, Suzumi."

Hearing her sister's words, the girl was immediately silent, she was very ashamed if Zenitsu really would hear her crying sound.

* * *

3 years later, Suzumi became Gems Pillar, she was 16 years old and close friends with Shinobu and Kanao.

She lived alone, her sister, Kurumi, was killed by mysterious demon she never heard 1 year after that conversation.

Fortunately, she was learning about gems breathing from her sister, and tried hard everytime until she became gems pillar after her sister died.

Suzumi was really angry, they killed her only family, she was determined to take revenge. However.

Suzumi wore her gems gradation-colored haori, which was her sister's. She got out from her house to meet Mitsuri. Mitsuri had just harvested honey and she invited Suzumi to feast on honey-based foods and drinks.

"So, you have best friend whose now whereabouts are unknown?" asked Mitsuri while taking a honey cookie.

"Yes, although he was crying-baby, but he was strong, I know it, but now I don't know how he is." Suzumi looked her honey-based drink in her cup.

"Ah, I feel sorry to hear that. But don't worry, I'm sure you will meet him again."

"Thank you, Kanroji-_san, _I hope that too."

After Mitsuri's house, Suzumi went to butterfly house, she want to ask Shinobu how was the mission in Mt. Natagumo. She heard that one of twelve demon moons was killed, and she want to listen the story.

When arrived at butterfly house, Suzumi didn't see anyone in the yard. _'Must be there are patients here.'_

As usual, she directly walked to Shinobu's room. "_Konnichiwa, _Saiwai-_san_," Aoi greeted, she was bringing clothes with her hands.

"Ah, Aoi-_chan... _Look like you're so busy today," Suzumi said.

"_Hai, _this all because of those three having wounds whole their body, but it's ok now."

"Those three?"

"Tanjirou-_san, _Zenitsu-_san, _and Inosuke-_san,_ they are new demon slayers who have recently joined."

"Oh... It must be hard." Suzumi nodded her head, she just knowing Tanjirou, who had little sister that changed to demon.

"Then I'll excuse myself first, Saiwai-_san, _I have to give them this change of clothes."

"No problem, I have to meet Shinobu-_san _anyway." Suzumi smiled then Aoi left her in a hurry.

Suzumi continued to walking to Shinobu's room when suddenly she just realized Aoi's words earlier.

_"Tanjirou-san, Zenitsu-san, and Inosuke-san, ..."_

_'Ah, it's impossible that's him, it must be other person with same name.' _

* * *

"Ah, yesterday Tomioka-san who killed the lower fifth of twelve demon moons."

"_Sou desu ka..._"

"At the first Tanjirou-_kun _who was cutting off the demon's neck by his _nichirin _but the demon tricked him."

"By the way, I heard there was demon family there."

"You're right, Saiwai-_san... _I killed the sister, Tomioka-_san _killed the father, Tanjirou-_kun _and Inosuke-_kun _killed the mother, and Zenitsu-_kun _killed the brother."

"So, they got hurt because of that."

"You know? I'm so proud of them, they are new members but able to kill strong enemies."

"I was surprised because what I knew Zenitsu-_kun_ is a coward, it turned out he is strong too, his body was hit by deadly spider poison."

Suzumi took a breath, it was same with Zenitsu whose her best friend.

"Tanjirou-_kun _and Inosuke-_kun _too, they weren't from family which have ability to use _nichirin _and kill demons."

"Yeah, I agree with you, their teachers weren't from their family."

"Just not like us, we learn from our family too."

Suzumi felt sadly again, she remembered her father and her sister, they said that they use _katana _to fight the villains but the fact is they fight monsters.

"Ah, I have to see them now, do you wanna see them too, Saiwai-_san_?" asked Shinobu while standing from her chair.

"Yeah, I wanna see them, they have warm heart that make me curious."

Shinobu and Suzumi got out from the room and walked together to the room where the trio squad were treated.

**_Chapter 1 - end _**

Mind to review? :))

Please leave comment, follow, or love

Thanks for read the first chapter


	2. Chapter 2

**{I'm sorry for grammatical errors, wrong vocabularies, etc. because English is not my main language, but I hope you can enjoy my story :)}**

_"Ah, I have to see them now, do you wanna see them too, Saiwai-san?" asked Shinobu while standing from her chair._

_"Yeah,__ I wanna see them, they have warm heart that make me curious._"

_Shinobu and Suzumi got out from the room and walked together to the room where the trio squad were treated._

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**Kimetsu no Yaiba**

**Credit : Koyoharu Gotouge**

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* * *

**Chapter 2 **

* * *

"Jeez..." Aoi got out from the room where Kamaboko Squad were treated.

As she met 2 pillars, she greeted them, Shinobu asked why she seems like angry, but she said she doesn't angry, just feel a little upset at the yellow haired boy who is difficult to close his mouth, always screaming that he doesn't want to take his medicine.

"For the first time I hear something like that," Suzumi said.

"Yeah, I think he has a very unique personality."

"Zenitsu, calm down, Aoi will never hurt you," Tanjirou said to Zenitsu who was acting like someone would kill him, his whole body was extremely tremble.

"How can you say like that?! I know that your medicine is easy to take but don't say like that to me!" Zenitsu yelled while his index finger pointed to Tanjirou.

When they arrived in front of the room, Suzumi was silent, her eyes focused on that yellow haired boy. She felt familiar with him, but she didn't remember who was him. Someone from her past? maybe.

Suzumi entered the room after Shinobu, she saw three boys were on their bed.

"How's your condition?" Shinobu asked them.

"Much better. Shinobu-_san_, thanks for bring us here." Tanjirou answered, his friend, Zenitsu, was looking at the girl whose staring the room ceiling.

_'She's so beautiful... no, no, no! Nezuko-chan more pretty than her.'_ He immediately shook his head.

_'But... I think I've known her before...'_

"Zenitsu!" Tanjirou called.

"W-what?"

Shinobu smiled, she intended to introduce the girl who standing behind her, "She is Saiwai Suzumi, the gems pillar, I think Tanjirou_-kun _has known her since yesterday, then I introduce her to both of you, Zenitsu-_kun, _Inosuke-_kun._"

Inosuke was just silent, he didn't even get up from his bed, he was so depressed.

"I'm Suzumi, nice to meet you." Suzumi shook Zenitsu's hands.

"N-nice to meet you too," Zenitsu replied nervously.

"I heard that you were hit by spider poison, I hope you can get well soon, and also your friends."

"T-thank you."

"Suzumi-_san,_ I heard you have a sister who was pillar too, is that right?" Tanjirou asked.

"Eh? Where did you hear that, Tanjirou?" Zenitsu asked curiously.

"That's right, but... my sister has passed away few years ago... that's why I replaced her as a gems pillar," She answered, her tone becomes low.

"Ah, sorry to hear that." Tanjirou felt guilty to made Suzumi remembered her past.

"No problem, I think we're same, just forget it."

Suddenly, a crow wearing a necklace made of small diamonds came to the window. "Saiwai Suzumi, Saiwai Suzumi, you were called by _Oyakata-sama, _he has waiting for you at his residence."

Suzumi took a breath. "Well then I have to go now, see ya." She said and walked out from the room quickly.

"That girl..." Zenitsu whispered involuntarily.

"What's wrong with her, Zenitsu-_kun_?" Shinobu asked.

"A, no... Nothing."

Zenitsu was thinking about the girl he just have met, he seemed to know her very well. A few seconds later, the shadow of his past best friend appeared in his mind.

"Suzumi-_chan... _Is that you?"

* * *

_"The kids__ have disappeared in the Aomori forest and no longer existed. Saiwai, go find them and help them to crush the demon that is there." _

_'I'm not surprised they disappeared, they must have been eaten by this damned monster.' _Suzumi said in her mind, she could smell the dead carcasses.

_'I hope my heart's fine...'_

"Cough... cough..."

"What's happening, Young Lady? Are you tired? Don't worry, you will be able to rest forever." The demon laughed loudly, he was satisfied after making Suzumi tired of his demon blood art that was 'disappearing undetected'.

"By the way, we haven't met yet, what's your name?" The demon smiled wickedly, he appeared in the form of a young man who looked the same age as Suzumi.

"Cough... cough..." Suzumi couldn't speak, her breathing was too tight for her weak heart. She just held her katana tightly.

"Alright, I will introduce myself first. My name is Kage which means shadow, I can hide even in your own shadow," he said proudly.

"Then why? Why I must know your name? It's not important for me," she said restrain her anger.

"Tch, you aren't suitable to be angry. Listen, you have great power, we can be friends if you want."

"No, I don't want to be your friend, you're just a monster, you have eaten my friends!"

"Hey, hey, I only eat their hearts, I didn't eat their body."

When she heard it, her anger increased, her body trembled, it felt like she wanted to throw her katana directly at the monster.

"Well, it looks like I really have to finish you off right now." Suddenly Kage disappeared from Suzumi's view.

_'Calm down, Suzumi, he must be around here.' _She closed her eyes for a few seconds.

"Over there!" Suzumi immediately swung her katana behind her body, which made one of Kage's hands broken and temporarily removed his demon blood art.

_'This girl...' _He was so upset, he wanted to kill her and eat her immediately.

"Gem breathing third form..."

When Kage would launch an attack with his sharp claws that will immediately cut anything, Suzumi swung her katana to his neck very quickly.

"A blast of Chalcanthite flakes!" She yelled and managed to break the demon's neck instantly with all her strength.

* * *

"UWAAAAA!" Zenitsu yelled, he woke up from his sleep suddenly.

"Zenitsu? What's happening?" Tanjirou asked worriedly, he was reading a book while his friends slept.

Zenitsu's breath was panting, as if he had just had a bad dream, his face paled.

"Tanjirou..." He called Tanjirou's name as if to cry.

* * *

"Haah... Haah..." Suzumi stunned, she saw the sight of the demon's body that slowly turned into ash.

_'Nee-chan, please forgive me, I shouldn't have used that power... please forgive me, Nee-chan...'_ She clenched her fist tightly in front of her chest.

"DAMN YOU! HOW DARE YOU CUT MY NECK? JUST LOOK, I'M WAITING FOR YOU IN THE HELL!"

"Shut up! I won't go to the hell and won't meet you." Suzumi replied angrily.

When all the ashes have disappeared, a warehouse appeared where there was demon slayer's corpses, Suzumi really wanted to cry when she saw those who died tragically. _'I'm really sorry, I can't help you all.'_

She called in several _kakushi_ to take care of the bodies of the demon slayers then left that terrible place.

**_Chapter 2 - end _**


	3. Chapter 3

**{I'm sorry for grammatical errors, wrong vocabularies, etc. because English is not my main language, but I hope you can enjoy my story :)}**

_When all the ashes have disappeared, a warehouse appeared where there was demon slayer's corpses, Suzumi really wanted to cry when she saw those who died tragically. 'I'm really sorry, I can't help you all.'_

_She called in several kakushi to take care of the bodies of the demon slayers then left that terrible place._

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**Kimetsu no Yaiba**

**Credit : Koyoharu Gotouge**

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* * *

**Chapter 3**

* * *

After giving a report to _Oyakata-sama, _Suzumi went to her house, she held the pendant necklace she was wearing tightly all the way.

_"Nee-chan, are you going to die someday?" _Suzumi asked, she was very afraid that her only sister would leave her alone forever.

Kurumi smiled, patted her sister's head. _"Yes, I am, but you too, Suzumi."_

Suzumi's question didn't mean like that, she had bad feeling she couldn't with her soon.

_"Don't worry, we can meet mama and papa if we die, Suzumi."_

_"Until that time, I will always take care of you."_

_'But you broke your promise to me, you left me first.'_

When Suzumi was about to arrive, she saw a yellow haired boy standing in front of her house, she immediately wiped the tears from her eyes so he wouldn't see it.

"_Konnichiwa, _Zenitsu-_san, _what are you doing here? How's your treatment?" Suzumi greeted.

"Ah, Suzumi-_san... _It's ok, Shinobu-_san _has allowed me to come out for a while."

"So that's it."

"Ummm... Suzumi-_san, _actually I came here because I have something to talk with you."

"I see, then come in."

"Suzumi-_san..._" Zenitsu called, he even didn't move from his position.

"Yes?" Suzumi turned her head.

"Don't you remember me?"

Hearing that question, Suzumi lifted one of her eyebrows. "What did you ask? Have we ever met before?"

Zenitsu sighed, he began to doubt whether Suzumi who was standing a few inches in front of him was his best friend.

"You're not here just for that question right? Just come in, it's getting cold outside."

When Suzumi would turn her body to left, Zenitsu's eyes caught the pendant necklace she was wearing.

"Suzumi-_san... _No, Suzumi-_chan,_" Zenitsu called with both his eyes closed by his hair bangs.

Suzumi gasped when she heard Zenitsu calling out her name with_ '-chan',_ she can only stare at Zenitsu without doing anything. Zenitsu walked over to her and put his hands on her shoulders.

"Long time no see, Finally we meet again."

Zenitsu hugged Suzumi, he was very happy to meet his best friend again. But not for her, she felt scared instead, she pushed Zenitsu away from her body with all her might.

"W-what are you doing? Why you hugged me? I don't even know who you are!" After saying that, Suzumi ran away to the forest, during this time there has never been an unknown man who hugged her arbitrarily, she was so afraid.

"Suzumi-_chan, _wait!" Zenitsu ran trying to chase her, lucky he could run so fast that he could follow her easily.

Meanwhile, Suzumi who knew that Zenitsu managed to chase her felt that her legs became weak and trembling because of her fear.

"Suzumi-_chan,_ do you hear me? I'm Zenitsu, we haven't seen in a long time since few years ago." Zenitsu yelled, but she didn't want to hear his explanation or... might not be heard by her.

_'Where should i go? He will definitely always follow me.'_

Suddenly she felt her heart ache, making her legs weak and stumbling against the stone until her body fell to the ground.

"SUZUMI-_CHAN_?!" Zenitsu yelled, he was very surprised when he saw Suzumi suddenly fell down.

"Suzumi-_chan_, are you okay?"

The helpless Suzumi could only look at Zenitsu who approached her without being able to do anything, she wanted to run but couldn't, her eyes blurred until finally everything turned black for her.

"Suzumi-_cha-_"

* * *

"Suzumi-_san_ have a weak heart from birth, so she could pass out at any time." Shinobu explained.

"Sorry to say like this, Zenitsu-_san_, but I think she won't live much longer."

"W-w-what?"

Shinobu sighed. "Don't worry, this is just my guess, if she can control her heart, I'm sure she can live long."

"How can?"

"With gems breathing, she can do it, because of that she never pass out during the fight,"

"but I don't know why she doesn't do it in normally."

"How about the medicine?"

"Weak heart isn't an illness, but I give her some vitamins to support her heart health."

Zenitsu looked Suzumi who was sleeping peacefully on the patient bed, his heart felt broken, why did he find out her 'illness' now even though they had been friends for a long time?

After Shinobu left the room, Zenitsu walked towards her and sat beside her bed.

_'Suzumi-chan, I'm really sorry to surprised you.' _Zenitsu said in his heart while his hands holding her hand.

After a while, Zenitsu let go of his grip on her, he pulled the two of pendant necklaces out of his pocket. Yes, he kept Suzumi's pendant necklace with him. When Zenitsu opened her pendant necklace, he saw two photos, one photo is Suzumi with her sister and one photo is Suzumi with... him.

_'She never even forget me.'_

* * *

"Hey, Zenitsu, where did you go?" Tanjirou asked when Zenitsu went back to their room.

"Monitsu, you should give me your dinner, I'm so hungry now!" Inosuke said loudly.

Zenitsu was just silent and walked to his bed.

"What's going on?" Tanjirou and Inosuke stared at each other in confusion with Zenitsu's strange behavior.

"Whoaa, what a beautiful pendant necklace, is it yours, Zenitsu?" Tanjirou asked.

Zenitsu didn't answer, he just shook his head. "Give me it, I want to see it too!" In an instant Inosuke snatched the pendant necklace from his hand.

"Hey, That's not mine!"

"Hey, isn't this Suzumi-_san_?" Tanjirou pointed to the photos.

"Hmmm... you're right, Monjirou, but... hey, isn't this Monitsu?!" Both of them were surprised, what happened actually? Gems pillar was in the same photo with black-haired Zenitsu! How can?

"We're close friends until I moved to another town without telling her, she must be very angry at me and remove our memories from her mind."

"Why you said that?"

"I tried to tell her but she avoided me and said that she even didn't know me."

"Zenitsu, I'm sorry but I don't think so, she never forget you, that's why she has kept your photo in her pendant necklace."

"But..."

"She just doesn't know who you're now, because your hair color has changed since she last saw you."

Zenitsu was amazed, might be Tanjirou's words were right, not long after he smiled. "Thank you, Tanjirou, I think you're right, sooner or later she will definitely recognize me."

Tanjirou smiled, he was happy because his close friend could smile again. Actually at first he was so surprised that Zenitsu had a pillar girl who was his best friend.

_**Chapter 3 - end**_


	4. Chapter 4

**{I'm sorry for grammatical errors, wrong vocabularies, etc. because English is not my main language, but I hope you can enjoy my story :)}**

_"She just doesn't know who you're now, because your hair color has changed since she last saw you."_

_Zenitsu was amazed, might be Tanjirou's words were right, not long after he smiled. "Thank you, Tanjirou, I think you're right, sooner or later she will definitely recognize me."_

_Tanjirou smiled, he was happy because his close friend could smile again. Actually at first he was so surprised that Zenitsu had a pillar girl who was his best friend._

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**Kimetsu no Yaiba**

**Credit : Koyoharu Gotouge**

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* * *

**_Chapter 4 _**

* * *

"Suzumi, wake up!" Someone said gently.

The sleeping Suzumi began to open her eyes slowly.

"_Nee... chan?_" Suzumi whispered.

Her eyes suddenly opened widely, her consciousness returned to full when saw her older sister.

"_Nee-chan? _Why you're here? Do you still alive?" She asked, couldn't believe what she saw in front of her eyes.

Kurumi smiled, "No."

"B-but... how can? Is this just a dream?" Suzuki pinched her cheeks so hard until she felt pain.

"Stop it, Suzumi."

Suzumi did what her sister said and stared at her.

"I can't say this is dream or not, but you're in a different world."

"Why I can't touch you? I wanna hug you!" Suzumi said with crying-like sound.

"Because you're still alive, you can't touch me even you came to this world."

"Wait! If this is world for who has died, so where's mom and dad?"

Kurumi tried to calm her sister down. "It's not like that, we can meet now because of the pendant necklace that I've given to you."

Suzumi was surprised, her mouth opened widely. "I gave it to you because I had feeling about this and... really happened."

Suzumi was going to cry, she never believe what just happened in her life. "I know you're here because you felt pain in your heart, isn't it?"

"Eh? How do you know it?"

"Suzumi... you really will be here, sooner or later, but I'm sure your time won't be long."

"Isn't that great? Our family can gather again." Kurumi put her index finger on her younger sister's lips.

"Do you have the heart to leave Zenitsu?"

"But... I never meet him again until now, _Nee-chan, _I have no reason to live longer."

"Don't you know he just met you?

"Huh? What do you mean?"

"That yellow haired boy is your old best friend, Suzumi! Don't you realize it?"

"That must be impossible." Suzumi chuckled.

Kurumi could only sighed, for couples of second she realized something, "Suzumi, where's your pendant necklace?"

"Huh? Why did you ask it? Of course I'm wearing it." She answered while touching her neck area.

"Eh?" She swallowed her saliva when she realized it was not there.

Kurumi looked her without any expression, her sister searched her pendant necklace worriedly, she didn't want to lost it.

"You can't meet me without that thing, Suzumi." After saying that, Kurumi's form disappeared from Suzumi's view slowly.

"_Nee-chan, _wait!!" She screamed, but in vain, suddenly her body was thrown to her real world.

"**_KYAA_**!!!" Suzumi woke up surprisingly, her breath panting.

Tanjirou, who happened to be asked by Shinobu to look after her, was shocked by her screams.

"Suzumi-_san, _are you okay?" Tanjirou asked worriedly.

Meanwhile, she was just silent, her breath was panting, she pulled her hair tightly, her eyes were so stiff.

"Tanjirou-_san..._ where's my pendant necklace?" She asked.

"Pendant necklace?" Couple of seconds, he remembered the thing that he looked with his squad.

"Ah, yours is..."

"I keep it with me." Zenitsu appeared with Inosuke behind him.

She was surprised, why he had her necklace with him?

Zenitsu walked to her and align his body with her. "This yours, Suzumi-_chan."_ He stretched out his hand to give her the necklace.

"T-thank you." Suzumi received it doubtfully, then she hugged the necklace given by her sister, the most valuable gift for her.

Zenitsu smiled, "Do you remember? I have it too," he said while showing his pendant necklace.

She was just silent, remembering her sister's words that Zenitsu who standing in front of her now is her best friend. The memories of her past with him appeared in her mind.

Suddenly, she hugged him tightly which made people in the room surprised, especially Zenitsu himself. "Where have you been all this time? Why you left me suddenly?" She asked loudly, tears dropped from her eyes.

Zenitsu hugged her back, "I'm so sorry, Suzumi-_chan_, I can't tell you everything that happened to me..." He said guilty.

"But, I'm glad you're okay... Please forgive me, I know I'm not a good friend to you..."

Both Tanjirou and Inosuke, they were touched by what they saw before their eyes.

* * *

Tanjirou and Inosuke have left the room, they wanted to give a chance to those two for talking each other.

"Suzumi-_chan, _why you become a demon slayer?" Zenitsu asked, he sat on the chair next to her.

"My sister... she was killed by them." Hearing Suzumi's answer, he was shocked.

"Do you mean... Kurumi-_san?_ No, it must be impossible!" Zenitsu denied, unbelieved with her words.

"But it happened, maybe you don't know that she's... a demon slayer too."

Both his eyes were widen, he was too shocked hearing the fact.

"Because of that, I don't want to lose this necklace besides I have another reason why I can't lose it."

"So, Zenitsu, I think this is your turn to tell me why you become a demon slayer," she said while looking at him.

"Um, yeah, actually I'm ashamed to tell you my reason, Suzumi-_chan._" He chuckled as he rubbed his back hair.

"I... had a lot of debt... then someone whom I considered my own grandfather was kind enough to pay all my debts, but instead, I was trained by him to be his successor," he explained.

"Debts? Why didn't you tell me? I could help you with it."

"I can't... I don't want to trouble my own friend."

"You know? I cried a lot because all of my beloved people left me," she said in a trembling voice.

Zenitsu's mouth was opened, he felt guilty to didn't know her feelings.

"But... you don't need to worry about me, because we can meet again now, Zenitsu." She smiled which made Zenitsu feel a little relieved.

"If so, from now on we will not separate anymore." Zenitsu gestured with his pinky finger.

After Suzumi did same as he did, Zenitsu did the pinky swear to her which means they promised never to leave each other like they used to, or maybe.. just him.

**_Chapter 4 - end_**

**Hello, I'm back (・・)**

**Sorry to not updated for a long time because I'm so busy working for my artworks ~**

**If you want to look my artworks, just visit my pixiv ID : ko_suzu10**

**Thank you~**

**Note : I'm going to fix this story after I write all the chapters, thank you for your understanding :) **


	5. Chapter 5

**{I'm sorry for grammatical errors, wrong vocabularies, etc. because English is not my main language, but I hope you can enjoy my story :)}**

_"If so, from now on we will not separate anymore." Zenitsu gestured with his pinky finger._

_After Suzumi did same as he did, Zenitsu did the pinky swear to her which means they promised never to leave each other like they used to, or maybe.. just him._

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**Kimetsu no Yaiba**

**Credit : ****Koyoharu Gotouge**

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* * *

**_Chapter 5_**

* * *

"Nezuko-chaaan~" Zenitsu said while tickling Nezuko's feet, made her laughed. Suzumi smiled, she was happy to see Nezuko's high-level cuteness.

"Zenitsu, you like this girl, right?" A question came from Suzumi made him surprised.

"Ah, n-no, it's not like that," he said, didn't want to admit the fact.

"Hmph, the look on your face says otherwise, after all your speech is nervous like that."

Zenitsu was silent, he knew that he couldn't lie to the girl who sat next to him. "A-actually... yeah, I like her." He admit while his fingers on his cheek, he choosed to looking around except her.

"I'm not surprised."

"But Zenitsu, I hope you really love her, don't do what you did to other girls before," she said while patting Nezuko's head.

"Eh? EH?!!" Zenitsu was shocked, his face turned to red.

Suzumi moved her finger to her chest, pointed to her heart. "I can feel it, that's why I know you like this cute girl." She smiled with both the eyes were closed.

When she played with Nezuko again, Zenitsu secretly watching her, he remembered Shinobu's words, she had heart problem and maybe won't live much longer.

Zenitsu started to crying silently, how can she would leave him for the second time even though they have just met.

* * *

_"Zenitsu, please come to my house, Onee-chan cooked lunch for you too."_

_"Zenitsu, look! I found a cute cat.__"_

_"Thank you for the gift, Zenitsu. I like it so much."_

_"Zenitsu, happy birthday! This is a little gift from me, but I hope you like it."_

_"Zenitsu, Onee-chan made pendant necklaces for us, she said I must give it to you－"_

Tanjirou woke up from his sleep, he saw Zenitsu who were beside him sat with his back to him. "Zenitsu, what's going on? Usually you sleep at this hour."

He did not answer right away, his wistful eyes still focused at his necklace which he held.

"Tanjirou..."

Heard his name was called, Tanjirou woke from his bed.

"Am I wrong if I let someone die?" he asked with his bangs closed his eyes.

Tanjirou was stunned to see Zenitsu's attitude changed dramatically, especially when he heard the question. "Why did you ask like that?"

"Because... someone will leave me for the second time, and never come back forever."

"Someone you mean ... is it Suzumi-_san_?"

That yellow-haired boy bit his lower lip. "Yes..."

"Monitsu, is it because her heart problem?" Inosuke asked suddenly, made both of his friends surprised.

"Inosuke, where did you know that from?" Tanjirou asked.

"Ah, I overheard Monitsu and that Insect Pillar talking about this on the day when that girl was brought here because she fainted."

"So that's it."

"Yeah... And now I don't know what must I do."

"But Monitsu, can't she control her heart with breath of gems?"

"That's right but... she doesn't do it except when fighting demons, that's why I wanna ask her actually, but... I can't."

"I'm sorry why I didn't know her problem from the beginning, even though we were always together... This is my fault..." When Zenitsu started to cry, Tanjirou and Inosuke hugged him.

"This isn't your fault, Zenitsu... We don't know why Suzumi-_san_ hid it from you even though you're so close with her... There are some reasons we don't have to know it."

* * *

Shinobu was going to check Suzumi's condition until she found that the girl was not in her room.

"Kanao, did you see Suzumi?" Kanao who were in the garden shook her head without talking even a little bit.

"Aoi, do you know where is Suzumi?" This time Shinobu asked to Aoi who prepared for breakfast.

"Ah, Shinobu-_sama, _I'm really sorry, Suzumi_-san _decided to get out from here last night although I asked her to not leave." Hearing Aoi's explanation, Shinobu could only sigh, she feeling worried because she knew what would Suzumi do.

.

.

"Hey, Kentarou, why we are called by The Insect Pillar to her room?" Inosuke asked.

"I don't know, but I think something bad is happening." Tanjirou answered seriously.

"Maybe we will be told to training 24 hours non-stop." Zenitsu said in fear while tugging at Tanjirou's back shirt.

"Well, let's see later."

.

"Sorry for suddenly calling you here, guys," Shinobu said to those three who already sat down in front of her.

"No problem, Shinobu-_san..._"

She turned her gaze to Zenitsu, making him nervous. "W-what? Why suddenly you looking at me like that?"

"Actually I don't want to say it but I really need your help, especially Zenitsu-_kun..._"

The yellow-haired boy's eyes were widen, why is she expecting him the most from the squads? Even though he had thought he was the weakest of them.

"Your close girl friend... has left this place from last night."

They all were surprised, from now on, there are more things unexpected will happen.

"That's why are you willing to do it? in order to save her life... But if you don't want to do it, it's OK, I'll do it myself and ask Oyakata-_sama_'s permission not to carry out the mission that must I do this time."

They exchanged glances, their eyes signaling the opinion of the other before finally agreeing to do it. "Shinobu-_san, _don't worry, we will find her... Just do what is your duty," Tanjirou said representing his friends.

"OK, then I will tell you all a place that is likely to be her destination, I hope you guys return to being fine and not hurt to bring her back."

* * *

"Where are you? Come out please! Now it's late at night, why are you still not showing your sharp fangs and scratches?" Suzumi yelled while holding her nichirin sword.

There is no answer, the forest inside the mountain was very quiet, naturally because no one would live in such a scary place except for certain creatures.

She smiled, both of her blue eyes slowly turned black because of her anger. "Alright, if you don't want to come out, I will force you to come out and I will make sure you will taste the sharpness of this sword to make you turn into dust instantly."

Demon who is being sought by her is the one who killed her sister, she promised herself to keep trying to get revenge by sending the demon to hell.

From information obtained by her, Kurumi was killed in a forest called 'death forest' which is on a mountain not far from Mount Natagumo.

In fact, Oyakata-_sama_ had forbidden her to go there, but she was still desperate.

She thought she would be able to die peacefully after finding demon who had taken the life of the only her family member left at that time.

"Tch.. why is there a girl who set foot on my mountain at will? Have you ever permission before?"

She turned her body and was surprised to find the origin of the voice.

She saw a demon hanging on a tree branch while licking his finger, it seemed he had just enjoyed a delicious meal (of course it's human flesh and blood).

"Oh, wow! What a beautiful creature! Girl, I promise I won't kill and eat you if you want to marry me."

Hearing what just he said, Suzumi felt disgusting. _'Wait... If I'm not mistaken, he looks like a man whom I met few days ago.'_

"Hey, tell me... are you the one who killed my sister?"

"Hm? I don't even know who you are, and now you asking me about your sister? It's so impossible I know your sister."

"By the way, you haven't answered my question yet..."

"You must be lying! I'm sure you're the one who killed her!!"

The demon suddenly attacked Suzumi with his claws rapidly, causing her blood to flow out from her left face. "Shut up! You have such a beautiful face but make me sick of you! You know, all of demon slayers who came here are dead, so be careful with me."

She touched her face that felt sore, the demon attacked her while her guard was down until she could not fend off his attack.

"A, I remembered... Someone once said that he had killed a girl and one day her sister would definitely come for revenge, I never thought it was you."

Suzumi was surprised, actually who was the demon that killed Kurumi? Why he knew that she had a sister?

"You said 'he'... that's mean that person, no, that demon is male, right?"

"Huh... Whatever you say, it's definitely not me who killed her."

"Ok, it's finished, I don't have time to talk with you."

When the demon was going to leave, she prepared her katana to cut off the demon's head.

"Oh yeah, I forgot one thing... that I had promised not to let a human being live after entering this mountain!!" Right after saying his last sentence, a needle-like object came out of his hand and targeted it with lightning speed to her.

She quickly avoided him even though the devil kept moving to approach her. "Nice thing, but you can't kill someone like me with it."

"Huh... You won't be able to say that after receiving this!!" He attacked Suzumi with the same object but with a far different amount, making it difficult to find a gap.

_'Gems breathing fifth form... Typhoon Sapphire!' _Because of that form, she managed to reverse the direction of the needles.

_'Damn... She isn't an ordinary girl.' _The demon decided to confine her in a transparent, airtight cube full of poison to kill her slowly.

_"Among the demon slayers, there is such a thing as Pillars, their skills are the greatest of the others.Therefore, if you meet them, don't waste your energy to attack, just kill them immediately."_

_'From her strength it seems like she is indeed one of them...'_

_'Good, just by killing her I can get a higher position on that person's side.' _He smiled wickedly as he watched Suzumi moved her sword repeatedly so she could be free from the cube.

"Alright killer, face me now without resorting to cheating!" She shouted after being freed, but unfortunately a cloud of fog appeared that caused she to see nothing.

Suddenly the demon appeared right in front of her and immediately pushed her body to crash on the ground, he trapped Suzumi with his body so she could not move.

"Good try, but it's useless, you won't be able to beat me," he said while biting her neck with his fangs, both his hands hold her hands firmly.

Suzumi tried hard to release her body from him, but all changed after she felt a liquid entering her body through the bite.

"The poison I put into your body through my bite a thousand times stronger than the poison from the needles and the cube earlier, so it's better you pray now before death picks you up."

"If you hadn't been bad from the beginning I wouldn't have done this to you."

* * *

"We have to find her as soon as possible!" Zenitsu said, he walked in the front, not as usual.

"Hey, Kentarou... Is he really Monitsu?" Inosuke whispered to Tanjirou.

"No, he isn't Monitsu, but Zenitsu," he replied. A few seconds later, Tanjirou stopped in his steps followed by Inosuke.

"Hm? What's wrong?"

"Hey, you guys! Why do you stop your steps?!"

"Smells blood," he said seriously.

"Where, Tanjirou? From where you smell those blood??" Zenitsu asked while pulling Tanjirou's haori sleeves.

As time goes by, the smell of blood is increasingly smelled by Tanjirou's nose. "Here!!" Tanjirou ran to the source of the smell followed by his two friends.

* * *

_'Am I ... dead?'_

**_Chapter 5 - end_**

**Note : I'm sorry for using '-san', '-kun', etc. because I feel more comfortable with it as you can read without it**

**Thank you for your understanding c: **


	6. Chapter 6

**{I'm sorry for grammatical errors, wrong vocabularies, etc. because English is not my main language, but I hope you can enjoy my story :)}**

_"Smells blood," he said seriously.__"Where, Tanjirou? From where you smell those blood??" Zenitsu asked while pulling Tanjirou's haori sleeves._

_As time goes by, the smell of blood is increasingly smelled by Tanjirou's nose._

_"Here!!" Tanjirou ran to the source of the smell followed by his two friends._

**.**

**.**

**Kimetsu no Yaiba**

**Credit : Koyoharu Gotouge**

**.**

**.**

* * *

**_Chapter 6_**

* * *

"Shinobu-_san _said that this forest called 'death forest'." They paused while staring at the forest a few meters away from their feet.

"This forest just looks scary at noon. I guess it must be even scarier at night," Zenitsu said in fear.

"Then, do you want to enter this forest, Monitsu?"

Zenitsu swallowed his saliva, however he must eliminate his own fear in order to save his closest friend since long time ago. "Let's go!" he said as he quickened his paces.

**＊＊＊**

_'This demon is still above my body ... I ... have to fight him ...'_ Suzumi gripped her sword with the rest of her strength, her body weakened due to the effects of the poison she received from the demon.

_'This is bad, I can't take it anymore. I won't be able to do it with my body condition like this, this sword feels very heavy in my hand.'_

A few seconds later, she lost her consciousness, letting the demon who was still on top of her body laughed happily for successfully crippling the girl.

"Huh? Is that the strength of the pillar? I never thought the pillar that was called the greatest among your group turned out to be very weak."

No answer, of course the girl couldn't answer him, both of her eyes were closed.

"It looks like I have to eat you now," he said while moving his claws to tear her body to take her heart.

_"Suzumi, wake up!! Muster all your remaining strength to the whole body and use the first form of breath!"_

ＢＯＯＭ！！

The demon was thrown by the explosion just now which made him shock. "W-what just happened?"

He looked up and found the helpless girl standing on one of the branches of a tree, holding her katana with her eyes all white.

_'How can? She shouldn't be moving anymore now.'_

Suzumi jumped at the demon who did nothing because he was astonished, he could not understand why there was someone who did not immediately die shortly after receiving poison in her body.

_'I don't know if this will work or not, but I have to do it first.'_

_'Gems breathing eight form... Arsenopyrite Kerf.' _Just by an eye, she managed to hit the demon's neck with her katana before her body landed smoothly on the ground with her legs.

The demon touched his neck which was hit by the girl's katana strokes just now. _'Why? Why didn't she cut it right away? She just scratched my neck." _He turned his head to Suzumi who turned her back on him.

"With my remaining strength, I can't cut you, so I only scratched your neck with poisonous gem powder that comes out of my sword in accordance with the form of attack I use," she said before finally her body collapsed and her eyes no longer caught anything.

* * *

_'There are many scents of blood that I smell, but there is only one that is really new ...The smell of this blood is getting stronger, because all I know is that the blood belongs to human, then the worst possibility is that this blood belongs to Suzumi-san.' _Tanjirou thought.

_'Apart from that, there is a demon scent too, it's certain that he inhabits this forest.'_

"Tontarou, watch out!!" Inosuke yelled and pointed to the ground.

"Hey, why there are many needles here?!" Zenitsu asked confusingly.

Tanjirou picked up one of them and then sniffed it. "This smell ... this is the smell of deadly poison." Hearing what Tanjirou did say, Zenitsu and Inosuke were surprised.

"How do you know it?"

"Its scent makes my whole body ache, if I smell it any longer I might die."

"We must be careful, these needles are obviously used to put poison into the human body."

"But, Monjirou, now it's noon, the demons will not come out."

"I know, but we still have to be careful, because there is demon who live here so there are likely to be many traps waiting for us."

"Tanjirou! Look!" The three of them were surprised to see that many trees in the forest were damaged, some trees fell on other trees, the condition was really chaotic.

"What really happened?" Tanjirou whispered.

_'Blood ... Needles ... Poison ... Trees ... Could it be ... Suzumi-chan ...?' _Without saying a word, Zenitsu darted away leaving his two partners.

"Zenitsu, wait!!" Tanjirou and Inosuke immediately chased him but in vain because Zenitsu ran as fast as lightning.

* * *

Suzumi saw all her family's shadows in the past, one by one appeared in her mind.

_'Nee-chan, I knew I didn't deserve to be a pillar, I could never be someone as great as you and dad ... my body was so weak, I couldn't possibly protect others even if only one person ... I'm just a hindrance to others ...' _She clenched her hands together, blood continued to flow from two small holes in her neck, occasionally the girl also vomited a lot of blood.

_'My head feels like it's going to break, my body can't feel anything anymore ... am I dead?'_

_"If so, from now on we will not separate anymore."_ Zenitsu's shadow suddenly appeared, so did his voice.

_'I'm sorry, Zenitsu ... I can't keep my promise to you.' _She closed her eyes slowly.

"Suzumi-_chan_! Please, hold on!! Don't close your eyes, please!! Don't leave me in this world alone!!" Zenitsu shouted about to keep Suzumi's awareness, he put her bloodied body on his thighs.

She opened her eyes again slightly. _'Zenitsu? Why is he here?'_ She thought when she saw Zenitsu's face staring at her with anxiety, his hand holding one of her hands tightly.

_'Oh yeah, maybe this is just my hallucination.'_ She smiled to him before she lost her consciousness again.

"No! Please, don't!" He hugged her with tears coming out of his eyelids.

"Zenitsu! What's wrong?" Tanjirou asked when he and Inosuke arrived at the place where yellow-haired boy was there.

"Tanjirou ..." He looked at Tanjirou with his flooded eyes, embracing a girl who did not look alive.

"Suzumi-_san_!" He ran towards them.

"I ... I was surprised when I saw that there are two small holes in her neck, the demon must have poisoned Suzumi-_chan _with his fangs," he explained while sobbing.

Tanjirou touched Suzumi's wrist, trying to find her pulse. "She is still alive, her heart rate is very weak, but maybe she can be saved even if the possibility is small," he said.

"Look, her left face was injured too, we must immediately bring her back to be treated."

Zenitsu nodded, he stood up while carrying her with both hands.

"Monitsu, let me carry her, it looks like you can't carry her with your condition like this," Inosuke said.

"No, I am her best friend so I have to carry her myself," he said refusing the offer of Inosuke who kindly wanted to replace him.

They immediately came out of the dense forest, bringing back the girl who was injured, especially on the inside of her body.

* * *

"I have examined the poison in Suzumi-_san_'s body and then I learned that the poison is not an ordinary poison, it is a poison that can kill a human in a few seconds," Shinobu said to Tanjirou and Inosuke a few days after that incident.

"Hard to say but it looks like Suzumi-_san_ won't be able to survive, given the condition of her heart which is also not good. There was not even a sign that she would wake up even though I had put the antidote in her body by injection."

"So that's it." Both of them could only sigh, couldn't imagine how Zenitsu's reaction would be if he heard that.

"But, is there any other way to save her life? Whatever it is ..."

"Of course I will try to find other ways to save her ... I'm saying this to be prepared in case the worst happens."

.

.

Zenitsu still crying, all the day, he was always beside the bed where Suzumi lay, he did not even want to join the training he should do. "Suzumi-_chan, _If you die, I must die too, we can't separate again as we promised, right?"

Aoi who peeked from behind the door really wanted to scold him for not participating in the training, but the fact that happened before her eyes made her have to forgive Zenitsu this time.

"Zenitsu-_san_, if you keep crying, Suzumi-_san_ might hate you. She doesn't want to have friend who crying all the time," she said as she placed several bowls of food on the table.

"This is your dinner, Shinobu-_sama_ told me to bring it here."

"T-thank you ..."

After Aoi left the room, Zenitsu looked at the face of Suzumi who was sleeping with a face that endured the pain. _'Is that right, Suzumi-chan? Do you hate someone like me who is a crybaby?'_

Suddenly, smol Nezuko appeared between them and Zenitsu almost fell in shock because of that. "Nezuko-_chan_? Since when were you here?!"

Ignoring Zenitsu's question, Nezuko touched Suzumi's neck with her small hand, a moment later a spark arose which finally burned Suzumi's entire body.

"WHOA!! WHAT ARE YOU DOING NEZUKO-CHAAAN??!" Of course, Zenitsu were really surprised to see what was happening right before his eyes.

**_Chapter 6 - end_**

**I think I'm gonna finish this story lol**

**What do you guys think?**


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